# find_tool ENVVAR NAMES...
# -------------------------
+# Look for some needed program. Use the value of the ENVVAR if set,
+# otherwise look for the first of the NAMES that can be run (i.e.,
+# supports --version). If found, set ENVVAR to the program name,
+# die otherwise.
find_tool ()
{
+ # Find sha1sum, named gsha1sum on MacPorts.
find_tool_envvar=$1
shift
- find_tool_name=$@
- if eval test x"\$$find_tool_envvar" = x; then
+ find_tool_names=$@
+ eval "find_tool_res=\$$find_tool_envvar"
+ if test x"$find_tool_res" = x; then
for i
do
if ($i --version </dev/null) >/dev/null 2>&1; then
- find_tool_res=$i
- break
+ find_tool_res=$i
+ break
fi
done
+ else
+ find_tool_error_prefix="\$$find_tool_envvar: "
fi
if test x"$find_tool_res" = x; then
echo >&2 "$0: one of these is required: $find_tool_names"
exit 1
fi
($find_tool_res --version </dev/null) >/dev/null 2>&1 || {
- echo >&2 "$0: cannot run $find_tool_res --version"
+ echo >&2 "$0: ${find_tool_error_prefix}cannot run $find_tool_res --version"
exit 1
}
- eval "$find_tool_envvar=\"$find_tool_res\""
+ eval "$find_tool_envvar=\$find_tool_res"
eval "export $find_tool_envvar"
}